Long term atrial fibrillation monitor

ABSTRACT

A cardiac arrhythmia monitor provides electrodes to allow daily ECG measurements of a patient without cumbersome electrode connection to the patient. ECG data may be diagnosed by the monitor to indicate likelihood of an arrhythmia and an indication provided to the patient ECG data based on that indication may be forwarded to a physician or other healthcare professional for a review.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 09/827,551 filed Apr. 6, 2001.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to electronic devices for detectinga cardiac arrhythmia and in particular to a device providing improvedpatient mobility and reliable long-term monitoring.

[0003] The human heart normally beats anywhere from 60 to 80 beats perminute when a person is at rest. Diagnosis of cardiac arrhythmiasnormally requires that a qualified professional review anelectrocardiograph (ECG) in which the electrical impulses from the heartare recorded and displayed in chart form. The electrical impulses aremeasured by electrodes attached at a number of locations to thepatient's chest. Certain episodes of cardiac arrhythmias, althoughserious, can be unnoticed by the patient. For example, it is desirablethat chronic atrial fibrillation be treated within 48 hours of itsonset.

[0004] One possible solution is the use of a “cardiac event recorder”, aportable ECG recording device carried by the patient and communicatingwith electrodes worn under the patient's clothing and adhesivelyattached to the patient's skin. Such recorders may provide algorithmsfor monitoring the ECG signal and may report to the users, for example,that atrial fibrillation has begun. Recorders of this type may alsorecord a rolling “window” of ECG data using solid state computer memory.In this latter case, the recorded ECG data may be transmitted over phonelines or the like for review by a qualified physician.

[0005] Unfortunately, the cardiac event recorder is not a practical toolfor providing a warning of the onset of certain cardiac arrhythmias thatcan occur unexpectedly at any time in later life. The need for thepatient to carry the cardiac event monitor about during the day and thecontinuous attachment of electrodes is impractical for long termmonitoring that may span decades.

[0006] What is therefore needed is a less cumbersome, and morepatient-friendly, apparatus and method for detecting cardiac arrhythmiasthan currently achieved.

BRIEF SUMMARY OF THE INVENTION

[0007] The present inventors have recognized that monitoring ECG signalsat a regular daily time for a brief period can reliably detectincidences of an arrhythmia. Such regular monitoring can be provided bya unit, which makes only momentary electrical contact with the patient,possibly contact with the patient's hands. An immediate evaluation ofthe patient's ECG signals is made, and if no arrhythmia is found, thepatient is so informed and may go about his or her business for theremainder of the day, unencumbered by monitoring leads and equipment.The present invention thus opens the possibility of extremely long termmonitoring of at risk patients with minimal intrusiveness to thepatient's daily life.

[0008] Specifically then, the present invention provides a monitor fordetermining the existence of an arrhythmia including a first and secondmomentary contact electrode sized to contact the patient. A detectorcircuit communicates with the first and second momentary contactelectrodes and executes a stored program to receive an ECG signal from apatient touching the first and second momentary contact electrodes anddetect a likelihood that the patient is experiencing an arrhythmia. Anoutput signal is provided to the patient if the likelihood is above apredetermined threshold.

[0009] Thus it is one object of the invention to provide a method formonitoring a patient for an arrhythmia that is far less intrusive thantypical cardiac evaluation monitors using chest electrodes and thuswhich makes long term monitoring possible.

[0010] The first and second momentary contact electrodes may be portionsof handles graspable by the patient's right and left hand or may befinger pads or posts sized to contact the patient for an ECG reading.

[0011] Thus it is another object of the invention to provide fortabletop or even smaller monitor implementations, the latter of whichmay be easily carried with the patient.

[0012] The output to the patient may be an illuminating indicatorindicating whether an arrhythmia was found, or an LCD display, vibratingmotor, or audible alarm.

[0013] Thus it is another object of the invention to provide immediatefeedback to the patient as to whether there is a likelihood of anarrhythmia.

[0014] The monitor may include a recording media and the detectorcircuit may record the received ECG signals subsequent to the patienttouching the first and second momentary contact electrodes. The ECGsignals may be the patient's current ECG signals or those recordedpreviously during the patient's use of the device.

[0015] Thus it is another object of the invention to provide not onlyindication to the patient of a likely episode of an arrhythmia, but alsoprovide a recording of the ECG signals for review by a qualifiedhealthcare professional.

[0016] The monitor may include a communication circuit and the detectormay communicate the ECG signals to the communication circuit fortransmission to a remote site.

[0017] Thus it is another object of the invention to simplify theprocess of reviewing the ECG signals by allowing the data to be readilycommunicated over communication media.

[0018] The monitor may include an alarm clock circuit providing a secondoutput signal to the patient to remind the patient to grasp theelectrodes. Further, the monitor may include a text displaycommunicating with the detector circuit to provide text messagesinstructing the patient in touching the first and second momentarycontact electrodes and remaining in contact with the elements prior togeneration of the output signal.

[0019] Thus it is another object of the invention to provide features tosimplify operation of the device and to encourage the patient in regularuse of the device.

[0020] The monitor may include a cascading memory for storing acquiredECG signals. ECG signals are tagged with a time of acquisition.

[0021] Thus it is an other object of the invention to replace olderacquired ECG data with more recent ECG data.

[0022] The monitor may include a nonvolatile memory for storing baselineECG data that can be compared to recently acquired ECG data to determinewhether a prolonged QT interval exists.

[0023] Thus it is another object to enable comparisons between recentlyacquired ECG data for a given patient and historical ECG data from thepatient.

[0024] The monitor may perform more than one method to determine whetheran arrhythmia exists.

[0025] Thus it is another object to provide redundancy when detectingthe presence of an arrhythmia.

[0026] The foregoing objects and advantages may not apply to allembodiments of the inventions and are not intended to define the scopeof the invention, for which purpose claims are provided. In thefollowing description, reference is made to the accompanying drawings,which form a part hereof, and in which there is shown by way ofillustration, a preferred embodiment of the invention. Such embodimentalso does not define the scope of the invention and reference must bemade therefore to the claims for this purpose.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a perspective view of a device for monitoring at leastone of a plurality of arrhythmias as constructed according to thepresent invention showing handles for supporting electrodes to begrasped by the patient, a patient display, and connections for receivingpower and communicating on the phone system;

[0028]FIG. 2 is a block diagram of the components of the device of FIG.1 showing connection of the electrodes through an ECG amplifier to ananalog to digital converter to be received and processed by amicrocontroller having memory for storage of ECG signals;

[0029]FIG. 3 is a flow chart showing steps executed by themicrocontroller of FIG. 2 in processing ECG signals from the patient;

[0030]FIG. 4 is a flow chart similar to FIG. 5 showing additional stepstaken for automatically downloading ECG data to a remote location forreview;

[0031]FIGS. 5a and 5 b are views similar to that of FIG. 1 of analternative embodiment for a compact atrial fibrillation device usingfinger pad electrodes or post electrodes instead of electrodes supportedin handles;

[0032]FIG. 6 is a diagram showing the path of information flow from thedevice to a central monitoring station for review by a qualifiedhealthcare professional and later communication to the patient and/orthe patient's physician;

[0033]FIG. 7 is a flow chart showing operation of a computer of thecentral monitoring station in managing the information flow of FIG. 6;

[0034]FIG. 8 is a schematic diagram of a cascading memory constructed inaccordance with the preferred embodiment;

[0035]FIG. 9A is a schematic diagram of an arrhythmia-free ECG signal;

[0036]FIG. 9B is the diagram illustrated in FIG. 9A with annotations todemonstrate various parts of the ECG signal;

[0037]FIG. 10 diagram similar to FIG. 9, but illustrating atrialfibrillation;

[0038]FIG. 11 is a diagram similar to FIG. 9, but illustrating atrialflutter;

[0039]FIG. 12 is a diagram similar to FIG. 9, but illustratingbradycardia;

[0040]FIG. 13 is a diagram similar to FIG. 9, but illustrating atrialtachycardia;

[0041]FIG. 14A is a diagram similar to FIG. 9, but illustratingventricular tachycardia;

[0042]FIG. 14B is a diagram similar to FIG. 14A, but illustratingventricular tachycardia with inverted P-waves;

[0043]FIG. 15 is a diagram similar to FIG. 9, but illustratingventricular fibrillation;

[0044]FIG. 16 is a flow chart illustrating steps to detect anarrhythmia;

[0045]FIG. 17 is a flow chart illustrating the steps to generate a modelof baseline data, as illustrated in FIG. 16;

[0046]FIG. 18 is a flow chart illustrating the steps to analyze acquiredECG signals, as illustrated in FIG. 16; and

[0047]FIG. 19 is a block diagram of the components of an ECG monitorconstructed in accordance with an alternate embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0048] Referring now to FIG. 1, a cardiac arrhythmia monitor 10 includesa housing 12 suitable for sitting on a tabletop, such as a nightstand ordresser. Monitor 10 is preferably portable and hence battery powered.Alternatively, a power cord 14 can extend from monitor 10 and be pluggedinto a wall outlet (not shown). A phone line connector cord 16 extendsfrom monitor 10 and can plugged into a conventional phone jack 18. Aprogramming connector 17 is also provided to allow programming of themonitor 10 by a qualified healthcare professional prior to use by apatient as will be described. While monitor 10 is particularlywell-suited for detecting atrial fibrillation, monitor 10 can also beused to detect a plurality of other cardiac arrhythmias, as is describedbelow.

[0049] The upper surface of the housing 12 includes a right and lefthandle, 20 and 22 respectively, providing on their undersurfacesmomentary contact electrodes 24. Momentary contract electrodes 24 may bebare metal surfaces, such as stainless steel plates, and aredistinguished from conventional ECG electrodes by the absence ofadhesive or other methods of affixing the electrodes to the patient'sskin and retaining them there. The electrodes 24 each contact one of thepatient's hands when the patient grasps the left handle 20 in thepatient's left hand and the right handle 22 in the patient's right hand.Those skilled in the at will appreciate that alternative electrodematerials could be used. Alternatively still, electrodes 24 can becapacitively coupled using techniques well known in the art, anddescribed in U.S. Pat. No. 4,922,375, the disclosure of which is herebyincorporated by reference.

[0050] One or more indicator lights 26 is positioned on the top surfaceof the housing 12 to provide an indication to the patient of thecondition of the patient's heartbeat. In the preferred embodiment, theindicator light 26 shows green when no irregularities are found in thepatient's heartbeat and red when a cardiac arrhythmia is detected. Thered light can be constantly illuminated or blinking depending on thecardiac arrhythmia that has been detected. For instance, detectingeither a prolonged QT interval or a ventricular tachycardia will prompta blinking red light.

[0051] A grating 28 in the housing 12 may provide for communication ofan audio, such as a tone or the message from an underlying speaker (notshown in FIG. 1). The audio may be used to remind the patient to take areading or to provide instructions to the patient and/or as a redundantindication of the detection of an arrhythmia augment the indicator light26. An LCD display 30 may provide for a graphic output including textinstructions to the patient as will be described below. Alternatively,monitor 10 may include a motor (not shown in FIG. 1) that vibrateseither along with, or instead of, the audio and/or LCD display 30.

[0052] Referring now to FIG. 2, the electrodes 24 are received by an ECGamplifier 32 of a type well known in the art and providing for noiserejection and ground referencing of the ECG signal. The output of theECG amplifier 32 is provided to an analog to digital converter 34 to beconverted to a set of digital signals that may be received bymicrocontroller 36.

[0053] Microcontroller 36 combines a microprocessor with one or moreinput/output ports and incorporates both volatile and non-volatilememory 38, the former holding programming and baseline data and thelatter providing a space for storing ECG signals. Two of theinput/output ports are connected to red and green indicator lamps 40providing light sources for the indicator light 26. A third input/outputport is connected to a speaker or piezoelectric audio transducer 42 forproviding tones or voice messages as may be appropriate to remind thepatient to take a measurement of his or her heartbeat and/or to providemessages for operation of monitor 10. A fourth set of input/output linesare connected to modem 44 which is connected to phone line connectorcord 16 for communication of data over the telephone lines usingstandard data communication protocols. The modem may either be connecteddirectly to the telephone lines, or may alternatively be connected to aspeaker that would output acoustic signals into a telephone handset forthe transmission of ECG data. While telephone lines are implemented inaccordance with the preferred embodiment, it should be easilyappreciated that the data transfer could be accomplished using one ofmany well-known alternative communication systems, such as the Internet,as will be described in more detail below. A fifth set of input/outputlines is provided to the programming connector 17 such as allowsprogramming of various parameters of operation of the monitor 10 as willbe described below. Finally, a sixth set of input/output lines isconnected to a motor 45 that vibrates as appropriate to remind thepatient to take a measurement of his or her heartbeat and/or to providean indication that a cardiac arrhythmia has been detected.

[0054] Referring now to FIG. 3, the program of the microcontroller 36may include an alarm clock routine 46 executing in parallel with themain program to provide alarm clock type functions well known in the artand, in particular, a tone at a regular time to remind the patient touse the monitor 10. This alarm clock routine operates according towell-known algorithms and the alarm time (and current time) may be setby attaching the monitor 10 to a programming computer via theprogramming connector 17. Alternatively, setting controls (not shown)may be provided on top of the housing 12 in the manner of a conventionalelectronic alarm clock.

[0055] The program of the microcontroller 36 also executes a loopindicated by decision block 48 detecting an ECG signal such as wouldindicate a connection by the patient's hands to the electrodes 24. Thisloop may simply detect the presence of an ECG signal detected bymonitoring the output of the analog to digital converter 34 or maydetect a resistance drop between the electrodes using separate circuitrywell known in the art.

[0056] Upon placement of the user's hands on the electrodes 24, themicrocontroller 36 starts a timer as indicated by process block 50 andmay provide a text display through LCD display 30 or a voice messagethrough audio transducer 42 to the user indicating that ECG acquisitionis being performed and instructing the user to retain his or her handsin position until the full elapsed time has expired. The timer value mayalso be displayed.

[0057] Following the starting of the timer, as indicated by processblock 52, data is acquired by progressively taking samples from theanalog to digital converter 34 and storing them in memory 38. Thepresent invention recognizes that stored data can be analyzed to detecta plurality of noteworthy arrhythmias.

[0058] Referring now to FIG. 8, a cascading memory 51 is provided involatile memory in accordance with the preferred embodiment. Memory 51includes a plurality of storage locations (anywhere from 5 to 100 slotsin accordance with the preferred embodiment), each storage locationstoring a sample of acquired ECG data. Each acquired ECG data sample istagged, either by microcontroller 36 or locally in memory 38, and storedin a memory storage location (e.g., one of slots 1-5), which isdetermined to be that storage location currently holding the oldestsample of volatile ECG data, as determined by the tag 55 associated withthe data. The tag can either be a time stamp, an indicator that can becompared to indicators of the other stored data to determine thechronological order of the stored data, or any other suitable ageindicator. In accordance with the preferred embodiment, the tag is atimestamp including a number of ticks that occur at a predetermined time(e.g., every minute). The oldest ECG data would then be identified bythe timestamp with the greatest number of ticks. Accordingly, oldest ECGdata is constantly replaced with newly acquired data.

[0059] Alternatively, only that ECG data indicating a likely arrhythmiacan be stored in the storage locations. Alternatively still, all ECGdata can be stored, whereby the tag would include an indication ofwhether the stored ECG data is normal or whether it indicates anarrhythmia and, if so, which arrhythmia.

[0060] The cascading memory thus enables the patient to transmit recenthistorical ECG data along with the recently acquired ECG sample to aphysician or other evaluating personnel, along with the previouslystored ECG data, if desired.

[0061] In addition to, or separately from, the cascading memory scheme,the present invention recognizes the advantages in storing baseline datafor a given patient either in nonvolatile memory, or in volatile memoryin a memory storage location (e.g., “slot 0”) that is not erased duringnormal operation. The baseline data is preferably stored in FLASHmemory, such that the data would not be erased upon a battery changes.The baseline data can include one or more of various data samples,including a baseline ECG data sample for the patient. The baseline ECGdata can be compared with subsequent ECG samples to determine whetherthe patient is suffering from a prolonged QT interval, as will becomemore apparent form the description below. The shape of the QRS complexfor the baseline ECG data can also be stored, either as the waveformitself or by storing critical data points that adequately describe thewaveform shape. It should furthermore be appreciated that baseline datasamples can be stored in nonvolatile memory on a regular basis (forexample once every year) to identify trends in the patient's ECG data.

[0062] Other baseline data can be stored and compared when analyzing apatient's real-time ECG data in order detect whether a patient isexperiencing a cardiac arrhythmia. Moreover, if an arrhythmia isdetected, the baseline data can identify the type of cardiac arrhythmiaamong a list of potential arrhythmias being tested for. This type ofbaseline data is referred to as “sample” baseline data throughout thisdescription, and is described in more detail below.

[0063] A stop timer signal, as indicated by process block 53, concludesthe acquisition of ECG data and signals the patient that he or she needno longer grasp the electrodes. The time interval for the acquisition ofECG signals is normally between several seconds (e.g., 2-3 seconds) anda few minutes (e.g., five minutes) and substantially less than a day, asis typical for use with conventional cardiac evaluation monitors.

[0064] Referring to FIGS. 9A-B, a normal ECG signal 150 is illustratedand includes a P wave 152 followed by a QRS 154 complex, which isfollowed by a T wave 156. The QRS complex includes an initial base (Q)158, a peak (R) 160, and a final base (S) 162. The P wave 152 has anamplitude that is approximately equal to 10% of the amplitude of peak160, while the T wave 156 has an amplitude that is approximately equalto 25% of the amplitude of the peak 160.

[0065] A number of arrhythmias can be diagnosed based on a patient's ECGdata. Supraventricular tachycardia, for instance, includes atrialfibrillation and atrial flutter. Atrial fibrillation develops when adisturbance in the electrical signals causes the two upper atrialchambers of the heart to quiver rather than pump correctly. When thequivering occurs, not all of the blood is forced out of the heart'schambers. The blood can pool inside the atrium and, at times clot. Bloodclots can cause a number of health problems, including a stroke if theybreak away and block an artery in the brain. As illustrated in FIG. 10,an ECG signal 164 of a person experiencing atrial fibrillation does notpresent a P wave. Moreover, the R-R interval (defined as the length oftime between R peaks of adjacent QRS complexes) is irregular when apatient is experiencing atrial fibrillation.

[0066] Atrial flutter occurs when the atria are stimulated to contractregularly at an accelerated rate (e.g., 200-350 beats per minute),typically as the result of electrical impulses traveling in a circularfashion around the atria. As illustrated in FIG. 11, atrial flutterwaves (F waves) are present instead of P waves in an ECG signaldemonstrating atrial flutter 166. F waves 168 are generally larger thanP waves, and present a saw-toothed waveform. A whole number fixed ratioof flutter waves to QRS complexes can typically be observed, forinstance 2:1, 3:1 or 4:1

[0067] It should be appreciated that the present device, whilewell-suited for the detection of atrial fibrillation and atrial flutter,can also detect other cardiac abnormalities if they happen to beoccurring at the time of the reading. Patients known to be predisposedto some of these abnormalities, which are more serious and require moreimmediate attention than atrial fibrillation, should be monitoredregularly, as opposed to using the momentary contacts of the presentinvention. Nevertheless, for patients who do not know about theseabnormalities, it is desirable for the present invention to also detectthese more serious conditions when monitoring for less urgentarrhythmias, such as atrial fibrillation, atrial flutter, or the like.

[0068] Bradycardia occurs when a person's heartbeat is slowed (typicallyless than 60 beats per minute), causing the patient to feel fatigued,dizzy, and lightheaded. Bradycardia can also cause fainting spells. Asillustrated in FIG. 12, the ECG signal demonstrating a bradycardiarhythm 170 is similar to a normal rhythm, except that the R-R intervalis longer and, occasionally, the P-waves might be abnormally wide.

[0069] Atrial tachycardia occurs when the rhythm is accelerated (e.g.,greater than 100 beats per minute). This condition can cause inefficientblood circulation, thereby causing a patient to feel palpitations, rapidheart action, dizziness, and lightheadedness. As illustrated in FIG. 13,the rhythm 172 for atrial tachycardia is similar to normal ECG rhythm150 with the exception that the RR interval is shorter (e.g., less than0.6 seconds). At very rapid rates, the P-waves might become superimposedon the preceding T waves such that the P waves are obscured by T waves.

[0070] Ventricular pauses are detected upon an abrupt halting of theheart rate (i.e., one or more dropped heartbeats) and can be detectedwhen the RR interval is greater than twice a predetermined “normal”value.

[0071] Premature ventricular contractions (PVC's) occur when theventricles beat prematurely before the normal electrical activationsequence of the heart has occurred, which can cause palpitations.

[0072] Ventricular arrhythmias that affect the beating of the ventriclesare more severe than those described above. Ventricular tachycardiaoccurs when electrical impulses originating from the ventricles causerapid ventricular depolarization (e.g., 140-250 beats per minute).During ventricular tachycardia pumping blood is less efficient becausethe rapid ventricular contractions prevent the ventricles from fillingadequately with blood. As a result, less blood is pumped to the body.The reduced blood flow to the body causes weakness, dizziness, andfainting. As illustrated in FIG. 14A, the QRS complexes 154 of aventricular tachycardia rhythm 174 are wide and chaotic. Alternatively,as illustrated in FIG. 14B, rhythm 174 can demonstrate inverted P-waves,resulting from ventricular impulses that are conducted backwards to theatria in some instances.

[0073] Ventricular fibrillation occurs when parts of the ventriclesquiver and beat ineffectively in a chaotic, uncoordinated manner,thereby stopping the pumping action necessary to circulate bloodthroughout the body. The ECG in ventricular fibrillation shows random,apparently unrelated waves. Usually, as illustrated in FIG. 15, no QRScomplex is recognizable in a ventricular fibrillation rhythm 176.

[0074] A prolonged Q-T interval also can, at times, indicate apotentially fatal arrhythmia if not treated, and can be detected byexamining the Q-T intervals in recently acquired ECG data with Q-Tintervals from baseline ECG data. For instance, a prolonged Q-T intervalcan be detected if the Q-T interval in recently acquired data reaches orexceeds a predetermined threshold greater than the baseline data.

[0075] After a suitable amount of data has been collected, analysis ofthe ECG signal for atrial fibrillation or other arrhythmia is begunusing a predetermined method, as indicated by process block 54. Suchmethods are well known to those having ordinary skill in the art, asdescribed in U.S. Pat. No. 5,350,404, the disclosure of which is herebyincorporated by reference. For instance, atrial fibrillation can bedetected by measuring the time interval between adjacent R waves (theR-R interval). If the R-R interval is chaotic (meaning that the intervalvaries from interval-to-interval beyond a predetermined variancethreshold well known in the art), then it is determined that the patientis experiencing atrial fibrillation.

[0076] Step 54 can also test for other cardiac arrhythmias. Inparticular, step 54 can test for atrial flutter by determining thepresence of F waves in the acquired ECG data. Likewise, Bradycardia canbe detected if the length of the R-R interval is greater than a presetthreshold. The threshold can be determined based on the user's R-Rinterval during a normal ECG signal. Tachycardia can be determined bymeasuring the R-R interval (e.g., less than 0.6 seconds). Ventricularfibrillation can be detected from the nonexistence of a QRS complex.Ventricular tachycardia can be determined by comparing the shape of theQRS complexes to previously stored QRS complexes, which were acquiredfor the user during a period of normal ECG data. If the recentlyobtained QRS complexes are wide and chaotic compared to previouslystored data, step 54 would determine that the user is experiencingventricular tachycardia.

[0077] While methods have been described above to determine whetheracquired ECG data demonstrates one of several possible cardiacarrhythmias, the present invention recognizes the advantages ofredundancy, and hence can perform more than one method to determine thelikelihood of an arrhythmia. In accordance with the preferredembodiment, a second method used to detect an arrhythmia involvescomparing recently acquired ECG data with the previously stored samplebaseline data described above. In particular, sample baseline data isacquired and modeled for a normal ECG signal along with each of thearrhythmias described above. Data from the acquired ECG signal is thencompared to models associated with each of the normal ECG signal andarrhythmias, and a likelihood is determined, based on the comparison ofthe acquired data to the models, which of the previously generatedmodels best matches the recently acquired ECG data. Based on the matchedmodels, monitor 10 can determine whether an acquired ECG signal isnormal, or that the ECG signal matches an arrhythmia. If either of thetwo methods for detecting an arrhythmia describe herein conclude that anarrhythmia exists, the patient will be alerted, as is described in moredetail below. Alternatively, both methods would indicate a positivereading before it is determined at process block 54 that the patient isexperiencing an arrhythmia.

[0078] Referring now to FIG. 16, the secondary arrhythmia detectionmethod 200 can be included, and begins at step 202, whereby a pluralityof baseline ECG data samples is acquired in a programming computer,which can be the same programming computer described above, or a centralcomputer that can communicate via telephone with a plurality of monitors10.

[0079] Each sample of data can either be of the patient(patient-dependent), or the data can be acquired from a pool of apredetermined number of patients (patient-independent) and averaged toderive a sample for a given rhythm class (i.e., normal data or aspecific arrhythmia that is to be tested). The patient currently beingtested need not be part of the pool that provides thepatient-independent data. Because the likelihood of obtaining sampledata from the patient for all conditions is low, and becausepatient-independent samples have been found to be robust and reliableduring operation, patient-independent data samples are preferred. Datasamples are preferably obtained for normal ECG data (i.e., data notexhibiting an arrhythmia), along with data samples for each arrhythmiathat is to be tested for during operation.

[0080] Next, at step 204, a model is generated for each ECG rhythmincluding any and all of the arrhythmias listed above along with anarrhythmia-free ECG rhythm from the data samples. In particular,referring now to FIG. 17 at step 210, each data sample (whichcorresponds to a predetermined ECG rhythm) is first filtered throughband pass filters several times to divide the signal into a plurality ofsub-banded signals (between 1 and 10, more preferably between 4 and 6,and more preferably 4) based on the frequency range of each sub-bandedsignal. In accordance with the preferred embodiment, the four signalsare divided into frequency ranges of 0.5-5 Hz, 5-10 Hz, 10-20 Hz, and20-30 Hz. It should be appreciated that any suitable set of frequencyranges could be used. Furthermore, each signal can be tagged, ifdesired, to maintain the identity of the signal.

[0081] At step 212, each sub-banded signal is segmented into a pluralitysegments of fixed lengths, the length being dependant upon the timeperiod needed to enable accurate ECG assessment. It is desirable toreduce the length of the segment while, at the same time, enablingreliable data. In accordance with the preferred embodiment, the fixedsegments are greater than one second, and more preferably equal to orgreater than two seconds. Next, at step 214, a reconstructed phase space(RPS) is generated for each segmented signal. The RPS is produced byplotting the original signal on an axis (e.g., the “x” axis) againstmultiple modified versions of the signal on other axes (e.g., the “y”and “z” axes). In accordance with the preferred embodiment, a modifiedsignal is phase shifted relative to the original signal. The phase shiftis preferably constant, and achieved by lagging behind the originalsignal by a predetermined fixed amount T or multiples of T (e.g., 2*τ).Phase shifted curves are produced in a multi-dimensional space, whichhas been empirically optimized as a 3-dimensional space with a lag of 20data points in accordance with the preferred embodiment. Accordingly,the original segmented curve along with two phase-shifted curves areplotted in a 3-dimensional space (i.e., phase space).

[0082] At step 214, the phase space can optionally be normalized based,for example, on the average unit distance to the center of the phasespace. Each sub-banded segment is normalized by dividing each point inthe RPS by the average point radial distance in the RPS from the origin.The normalization removes the patient-independent differences in theamplitude of the signals. At step 216, the normalized RPS of thesub-banded segment is added to the RPS of the other sub-banded segments.Next, at decision block 218, it is determined whether the phase spacehas been produced and combined for all segments of the current rhythm.If not, the next segment is selected in block 220 and steps 210-216 arerepeated for the next segment.

[0083] Once the phase space has been produced and combined for allsegments of the rhythm, process 204 proceeds to step 222, whereby aGaussian Mixture Model (GMM) is created for the combined RPS for allsub-banded RPSs of a given rhythm type. GMMs are well known in the art,and are described, for instance, in Richard J. Povinelli, Michael T.Johnson, Andrew C. Lindgren, Jinjin Ye (in press) “Time SeriesClassification using Gaussian Mixture Models of Reconstructed PhaseSpaces,” IEEE Transactions on Knowledge and Data Engineering, thedisclosure of which is hereby incorporated by reference as if set forthin its entirety herein. In particular, a set of GMMs are produced thatstatistically model the density of points in the combined reconstructedphase space. In accordance with the preferred embodiment, twentyGaussian equations are produced for a given phase space. Once the GMMsare produced for a given sub-banded phase space, it is determined atdecision block 224 whether all the sub-bands for the desired rhythm havebeen modeled. If not, the next sub-band is selected at step 226, andsteps 212-224 are repeated for all remaining sub-bands of the desiredrhythm. Once all sub-bands have been completed for a desired rhythm, itis determined at decision block 228 whether all desired rhythms havebeen modeled. If not, the next rhythm is selected at step 230, and steps210-228 are repeated for all remaining rhythms. Once all rhythms havebeen completed, process 204 proceeds to step 206 at step 229.

[0084] Referring again to FIG. 16, the GMMs for each rhythm aredownloaded into monitor 10, and stored in nonvolatile memory 38 at step206. Alternatively, GMMs could alternatively be downloaded into memory38 upon completion of each rhythm. It should be appreciated that the202-206 are preferably be performed preparatory to a patient usingmonitor 10 for ECG analysis. Next, referring to FIG. 18, monitor 10performs an analysis 208 to determine whether ECG data for a patientexhibits an arrhythmia. In particular, at step 232, once ECG data isobtained for a given patient in the manner described above,microcontroller 10 band pass filters the acquired data into sub-bands inthe manner described with respect to step 210. Next, at step 234,microcontroller 36 calculates a normalized phase space for the acquireddata in the manner described above, and stores the phase space involatile memory. Next, at step 236, microcontroller 36 compares thepoints that comprise the phase space calculated at step 234 to each GMMrelated to the sample baseline data for the current sub-band andcalculates the probability that the acquired signal is a particularrhythm. Next, at decision block 238, it is determined whether all of thesub-bands have been analyzed. If not, the next sub-band is selected inblock 240 and steps 234-238 are repeated for the next segment.

[0085] At step 242, the probabilities calculated in step 236 arecombined for each rhythm. At step 244, microcontroller 36 determineswhich set of GMMs most closely describes the points in the phase spacecalculated at step 242. In particular, at step 244, microcontroller 36determines that the patient's recently acquired ECG sample is eithernormal or arrhythmatic (and if so, which arrhythmia is matched) at step.At step 246, process 208 reverts to decision block 58 illustrated inFIG. 3.

[0086] Method 200 is further described in a publication entitled “RhythmClassification Using Reconstructed Phase Space of Signal FrequencySub-bands” by Felice M. Roberts, Richard J. Povinelli, and Kristina M.Ropella in Computers in Cardiology 2003, the disclosure of which ishereby incorporated by reference as if set forth in its entirety herein.

[0087] Upon completion of the ECG signal analyses, an arrhythmia will bedeemed to exist at decision block 58 when any of the methods describedabove indicate the existence of a cardiac arrhythmia. Advantageously,the present invention provides a redundant system for detectingarrhythmias, including atrial fibrillation, which is the most commonarrhythmia among humans. If no arrhythmia was found by any of themethods, as determined by decision block 58, then the green indicatorlamp 40 is illuminated and a text display may be provided to the patientvia LCD display 30 indicating that no atrial fibrillation was found perprocess block 60. This outcome may be stored in memory 38 along with theECG data and the memory 38 may hold ECG data and outcomes from previousmeasurements as a backup matter.

[0088] If an arrhythmia is detected then the program proceeds to processblock 62 and the red indicator lamp 50 is illuminated. Lamp 50 can beilluminated in various patterns to convey a particular arrhythmia (orclass of arrhythmias) to the patient. Alternatively still, a pluralityof colored lights can be provided, each color corresponding to anindividual arrhythmia or class of arrhythmias, such that illumination ofa given light will alert the patient to the arrhythmia, or type ofarrhythmia, that has been detected. Alternatively still, a text displaycan alert the user as to the detected arrhythmia.

[0089] With the indications of an arrhythmia, the patient may beinstructed (or have been previously instructed) to call his or herphysician and arrange for an in-office ECG to be taken.

[0090] Alternatively, as shown in FIG. 4, the microcontroller 36 mayundertake additional steps after process blocks 60 and 62. Specifically,after the green light at process block 60 has been displayed, themicrocontroller 36 may communicate with the modem 44 (or alternatecommunication system) to communicate with a central computer and reportpatient compliance in taking the measurement per process block 61. Thetransmitted data may include a time and a patient identification, thelatter stored in memory 38 and preprogrammed there via the programmingconnector 17 prior to receipt of monitor 10 by the patient per processblock 63. Optionally, the compliance signal may only be sent if a validECG signal was obtained.

[0091] When an arrhythmia is indicated at process block 62, instructionsmay be provided to the patient that data will be transmitted to acentral location and the patient is to wait for a confirming phone call,per process block 64, or to call the patient's physician. At succeedingprocess block 66 the modem 44 or alternate communication system isactivated, and at process block 68 a download of the data and thepatient identification is sent to the central location. The data may bereviewed there by the patient's physician.

[0092] As described above, instead of a modem 44 linked to phone lineseither directly or via an acoustic coupler, alternative communicationsystems may be used. For example, the ECG data may be transmitted to apersonal computer for subsequent transmission to the central locationvia the Internet. The personal computers could further be used to storethe ECG data either internally or on a storage medium such as a disc.Data may be communicated to the personal computer using one of manypossible communication circuitries. For example, the monitor 10 mayinclude a data transfer port, such as a Universal Serial Bus (USB),parallel, or serial port that is in communication with a correspondingport on the personal computer. Alternatively, the monitor maycommunicate with the computer via wireless communication, via, forexample, an infrared communications link. Alternatively still,Bluetooth™ wireless technology may be implemented by installing aBluetooth microchip incorporating a radio transceiver for communicationwith a corresponding Bluetooth microchip located in the personalcomputer.

[0093] Referring again to FIG. 2, the electrodes 24 may be spring-loadedto recess into the housing 12 slightly when pressed and thus may serveas operators for switches 25 communicating with the microcontroller 36to provide a signal indicating that the device is being used (detectedby process block 48) or to apply power to the device in the case whereit is battery operated and power must be conserved. Either or bothelectrodes 24 may be thus connected to switches which may also be usedto indicate to the user that the necessary pressure is being applied tothe electrodes 24 for good electrical contact.

[0094] Referring now to FIG. 5a, the goal of providing a convenientmechanism for long term monitoring of a patient for atrial fibrillationcan also be met by a pocket sized unit having finger pads 19 alsoproviding the electrodes 24 and operating on batteries so as to be seton a tabletop or be carried with the patient for travel. Of course, oneskilled in the art will recognize that finger pads 19 can also beengaged by a patient's thumb(s). A phone connection may be providedthrough a direct modulation of the piezoelectric audio transducer 42which may be held up to the telephone mouthpiece for use when thepatient is at or away from home. The modulation technique in this casemay be FM rather than the modem stile modulation of the modem 44described above. The remote site may in this case include a provisionfor the patient providing a contact phone number at which the patientmay be reached or may provide for the patient initiating a call with hisor her physician or a contact number at the remote site.

[0095] Referring now to FIG. 5b, as an alternative to the finger pads19, posts 21 may be used spaced so as to be held against the patient'schest across the heart for a reading of ECG signals.

[0096] Referring now to FIG. 6, a number of different patients 70 athrough 70 c may each have a corresponding monitor 10 a through 10 c. Atthe regular time for patient monitoring, patient 70 a through 70 c mayundertake the steps described above and patient identifications and/orECG signals may be sent over the standard telephone network 72 from themonitors 10 a through 10 c to a central computer 74 having dial-upcapabilities. It should be appreciated that network 72 could include awireless network (e.g., via cellular technology).

[0097] At the central computer 74, a qualified healthcare professional76 may monitor the transmissions 71 and, communicating with aphysician-patient database 78 and a compliance database 80, manually orautomatically make contact with various physicians 82 a through 82 c viastandard telephone receivers 84 or computer terminals 86, the lattercommunicating with a web server 88. The physician-patient database 78includes records linking particular patients, per patientidentifications loaded into the monitors 10, to physicians responsiblefor those patients. The physician-patient database 78 may include phonenumbers and e-mail addresses of the physicians and phone numbers of thepatients whose use will be described below. The compliance database 80includes records linking patients, per their identifications, to dateson which a compliance signal was received. As will be described, thesystem operates to make use of one or a limited number of qualifiedhealthcare professionals 76 to verify the judgments of atrialfibrillation algorithm of the monitors 10 a through 10 c so as to onlycall physicians 82 a through 82 c if required, reducing any possiblefalse alarms.

[0098] Referring now to FIG. 7, generally, the computer 74 operates toreceive ECG data and patient identification data as indicated by processblock 90. At decision block 92 the data is automatically analyzed to seewhether it is in response to a detection of a cardiac arrhythmia or issimply compliance data. If the data is compliance data, then the programproceeds to process block 94 and the patient compliance database 80 isupdated as indexed by the patient identification transmitted along withthe compliance data. If cascading memory scheme 51 is implemented, thedata is stored in the oldest memory slot and tagged with identifyinginformation, including the time of ECG acquisition along with anindication of normal or arrhythmatic ECG data along with, if applicable,an indication of the arrhythmia detected.

[0099] The data of the patient compliance database 80 may be posted tothe web server 88 for review by the physician typically using a passwordprotected review process. Alternatively, or in addition, a separateprogram 96 may periodically review the compliance database 80 to detectwhether compliance is being had and if not, to send e-mail to theappropriate physician using the patient's identification to locate theproper physician using the physician-patient database 78.

[0100] Referring again to decision block 92, if cardiac arrhythmia datahas been sent, that is, ECG data identified by the monitor 10 asexhibiting a cardiac arrhythmia, the ECG data is presented to thequalified healthcare professional 76 for a review as indicated byprocess block 98, including tag 55. The review may be by means of astandard computer monitor or may involve a printing out of the ECG data.

[0101] At decision block 100 the qualified healthcare professional 76determines whether the cardiac arrhythmia is actually present. If thequalified healthcare professional 76 concludes that the transmitted ECGdata shows a normal heartbeat (and that the monitor 10 was mistaken),then the program proceeds to process block 102 and the operator ispresented, based on the patient identification associated with the databeing displayed, with a phone number of the patient in thephysician-patient database 78. The operator may then call the patient toindicate that there was no cardiac arrhythmia so that the patient needno longer wait by the phone. Alternatively, this message may begenerated electronically through computer techniques well known in theart upon command by the qualified healthcare professional 76.

[0102] Referring again to decision block 100, if a cardiac arrhythmia isshown by the ECG data, after instruction by the qualified healthcareprofessional 76, the program proceeds to process block 104 and thequalified healthcare professional 76 is provided with the physician'sphone number from the physician-patient database 78. The qualifiedhealthcare professional 76 may then call a particular physician 82 athrough 82 c to note that their patient has a confirmed cardiacarrhythmia (e.g., an episode of atrial fibrillation) and to instruct thedoctor to review the ECG signals that have been posted to the web server88. Alternatively, or in addition, an e-mail message may be submitted tothe doctor attaching the ECG data as a graphics file according totechniques well known in the art. Again, this message may be providedautomatically either by synthesized voice over a standard telephonenetwork or by e-mail message.

[0103] In this way, a machine-diagnosed cardiac arrhythmia may beconfirmed by a single highly experienced individual, shared among manypatients, and a physician need only be brought into the loop when thearrhythmia has been confirmed.

[0104] In accordance with an alternate embodiment of the invention,monitor 10 can be worn on a patient's person. For instance, referring toFIGS. 19, monitor 10 can be connected to a strap 47 that can be fastenedaround a patients wrist or waist. It should be further appreciated thatmonitor 10 could be integrated into a wristwatch.

[0105] The electrodes 24 can be configured as described above withreference to FIGS. 4 and 5 and the alternatives described herein.Alternatively, monitor 10 can provide virtual momentary contactelectrodes 24, one of which extending outwardly away from the patient,the other of which extending inwardly from monitor 10 so as to be inconstant contact with the patient's skin. The outwardly facing electrode24 is engaged by a user's hand to begin data acquisition. Alternativelystill, both electrodes could face inwardly to be in constant contactwith the patient, and the microcontroller 36 would sample the patient'sECG data at predetermined time intervals upon the expiration of a presettimer. A manual override (not shown) can be provided on the face ofmonitor 30 in the form of a button or the like that the patient wouldactivate to initiate ECG data acquisition regardless of the timeinterval. Because only momentary data is acquired by the user-wornmonitor 10 having electrodes 24 in any of the configurations describedabove (e.g., one or more times per day) as opposed to constant ECGsampling, the electrodes are referred to herein as momentary contactelectrodes.

[0106] The patient-worn monitor 10 includes the components illustratedin FIG. 2. However, modem 44 is replaced with a communications moduleusing Bluetooth™ wireless technology by installing a Bluetooth microchipincorporating a radio transceiver for communication with a correspondingBluetooth microchip located in the personal computer. Alternatively,module 44 can communicate with the personal computer using infrared orany alternative well-known wireless technology.

[0107] The present invention further recognizes that advantages may beachieved using multiple arrhythmia detection methods in combination withan ECG monitor that does not include momentary contact electrodes, butrather uses permanent electrodes to continuously monitor a patent's ECGsignal (hereinafter referred to as a “permanent ECG monitor”). Thecomponents of permanent monitor 310 is illustrated in FIG. 19, andincludes reference numerals corresponding to like elements of monitor 10(illustrated in FIG. 2) incremented by 300 for the purposes of clarityand convenience. In particular, multiple channels of data may beobtained by attaching multiple contact electrodes 324 to the patient inthe known manner. For example, one contact electrode can be placed onthe patients left arm, another placed on the patients right arm, and athird electrode placed on the patients abdomen or one of the patient'slegs so that the electrodes form a triangle. Three channels of ECG datamay thus be obtained (each channel originating from adjacentelectrodes).

[0108] The multiple channels of ECG data are amplified by acorresponding one or more amplifiers 332, and fed into a correspondingone ore more analog to digital converters 334. Only one amplified 332and converter 334 is illustrated in FIG. 19. The output fromconverter(s) 324 is sent to a microcontroller 336, including volatileand nonvolatile memory 338. Controller 336 is connected to a programmingconnector 317, and one or more indicator lights 326.

[0109] A detector circuit of the type described above is thus connectedto each channel of data, such that the permanent ECG monitor can thendetermine which channel exhibits R peaks of the greatest amplitude, andanalyze the R-R interval of that channel to determine whether any R-Rinterval-dependent arrhythmias exist using the methods described above.Alternatively, any channel may be selected having an R peak greater thana predetermined amplitude. The other channel (or possibly the other twochannels) can be analyzed using method 200. Redundancy is thus achievedin the event that one of the contact electrodes is not adequatelyconnected to the patient. Furthermore, the implementation of twoarrhythmia detection methods achieves the benefits described above withreference to the momentary contact electrodes.

[0110] During operation, the permanent ECG monitor continuously readsECG data from the patient, and stores data from an immediately previoustime frame (e.g., the previous 2 minutes of ECG data) in volatilememory. The old data in volatile memory is thus constantly beingoverwritten with new data. If the monitor determines, based on either orboth arrhythmia detection methods, that the patient is experiencing anarrhythmia, an alarm can be activated on a display 357 (or by any othersuitable means), and the data residing in the volatile memory can becaptured and stored in nonvolatile memory 338 for future retrieval bythe attending physician. Data can also be captured from volatile memoryand stored into nonvolatile memory upon the activation of a button,switch, or the like 349, when the patient exhibits a symptom of acardiac arrhythmia.

[0111] It is specifically intended that the present invention not belimited to the embodiments and illustrations contained herein, but thatmodified forms of those embodiments including portions of theembodiments and combinations of elements of different embodiments alsobe included as come within the scope of the following claims.

We claim:
 1. A long-term monitor using scheduled short-term acquisitionof data from a patient for determining whether an arrhythmia selectedfrom the group consisting of at leas one of atrial fibrillation, atrialflutter, a prolonged QT interval, atrial tachycardia, PVC's, andventricular pauses exists, the monitor comprising: (a) a first andsecond momentary contact electrode for momentarily receiving ECG signalsfrom the patient; (b) a detector circuit communicating with the firstand second electrodes and executing a stored program to: (i) receive theECG signals from the patient touching the first and second momentarycontact electrodes; (ii) detect a likelihood that the patient isexperiencing at least one of the arrhythmias; and (iii) provide a firstoutput signal to the patient if the likelihood is above a predeterminedthreshold and otherwise providing to the patient a second output signalindicating that the likelihood is not above the predetermined threshold.2. The monitor of claim 1, further comprising a sensor in communicationwith at least one of the momentary contact electrodes and the detectorcircuit that activates the circuit only upon a determination that thepatient is touching the at least one contact electrode.
 3. The monitorof claim 1, wherein at least one of the momentary contact electrodes areconfigured to constantly contact the patient, further comprising asensor that activates the detector circuit only upon a determinationthat the patient is touching the other contact electrode.
 4. The monitorof claim 3, wherein both momentary contact electrodes constantly contactthe patient, further comprising timing circuitry that enables thedetector circuit to receive the ECG signals for a short period of timesubstantially less than a daily interval.
 5. The monitor of claim 4,further comprising an operator that is manually activated to enable thedetector circuit to receive the ECG signals.
 6. The monitor of claim 1wherein the momentary contact electrodes are handles graspable by thepatient's right and left hands.
 7. The monitor of claim 1 wherein themomentary contract electrodes are finger pads sized to contact thepatient's fingers on the left and right hand.
 8. The monitor of claim 1wherein the momentary contact electrodes are operators for switches andwherein the detector circuit communicates with the switches to monitorECG signals only when the switches are activated by a pressing inward ofthe switch operators by contact with the patient.
 9. The monitor ofclaim 1 further including an illuminating indicator and wherein thefirst and second outputs to the patient are different illuminations ofthe indicator.
 10. The monitor of claim 1 further including a recordingmedia and wherein the detector circuit further (iv) records the receivedECG signals subsequent to the patient touching the momentary contactelectrodes.
 11. The monitor of claim 10 further including acommunication circuit and wherein the detector circuit further (v)provides communication of the recorded ECG signals to communicationcircuit for communication to a remote site.
 12. The monitor of claim 1further including a communication circuit and wherein the detectorcircuit further (iv) communicates the ECG signals to the communicationcircuit for transmission to a remote site.
 13. The monitor of claim 12,wherein the communication circuit further comprises a telephone linecommunication circuit.
 14. The monitor of claim 1 further including analarm clock circuit providing an output signal to the patient to remindthe patient to contact the electrodes for a reading.
 15. The monitor ofclaim 1 further including a text display communicating with the detectorcircuit to provide text messages instructing the patient in touching themomentary contact electrodes and remaining in contact with theelectrodes prior to generation of the output signal.
 16. The monitor ofclaim 1, further comprising a cascading memory having a plurality ofmemory storage locations storing previously stored ECG data bearing atag, wherein newly acquired ECG data is stored in that storage locationwhose data has the oldest tag.
 17. The monitor of claim 1, furthercomprising nonvolatile memory operable to retain a baseline ECG signal,and wherein the received ECG signal is compared to the baseline ECGsignal to determine whether the likelihood of a prolonged QT intervalexists.
 18. The monitor of claim 1, wherein the output signals compriseat least one of a light, a vibrating mechanism, a display, and anaudible alarm.
 19. The monitor of claim 1, wherein the electrodes arecapacitively coupled.
 20. The monitor of claim 1, further comprising analarm clock circuit providing an output signal to the patient to remindthe patient to contact the electrodes for a reading.
 21. A method oflong term monitoring a patient for an arrhythmia selected from the groupconsisting of at leas one of atrial fibrillation, atrial flutter, aprolonged QT interval, atrial tachycardia, PVC's, and ventricular pausesusing a monitor having a first and second momentary contact electrodesized to contact a patient, and incorporating a detector circuitcommunicating with the first and second momentary contact electrode, themethod comprising the steps of: (a) touching at least one of themomentary contact electrodes; (b) at no more than a predeterminedinterval, collecting from the patient an ECG sample when the patienttouches the momentary contact electrodes, wherein the data is collectedfor a short period of time substantially less than a daily interval; (c)detect by the detector circuit a likelihood that the patient isexperiencing at least one of the arrhythmias; and (d) provide a firstsignal to the patient when the likelihood is above a predeterminedthreshold and otherwise providing to the patient a second output signalindicating that the likelihood is not above the predetermined threshold.22. The method of claim 21, wherein step (a) further comprises sensingthat the patient is touching at least one of the momentary contactelectrodes.
 23. The method of claim 21, wherein step (a) furthercomprises placing the contact electrodes in constant contact with thepatient.
 24. The method of claim 21 wherein step (b) is conducted in themorning after the patient wakes.
 25. The method of claim 21 wherein themonitor includes a recording media and including the further step of:(2) recording the received ECG signals subsequent to the patienttouching the first and second momentary contact electrodes.
 26. Themethod of claim 25 wherein the monitor includes a communication circuitand further including the step of: (e) communicating of the recorded ECGsignals to a remote site.
 27. The method of claim 21 wherein the monitorincludes a communication circuit and further including the step of: (e)communicating of the recorded ECG signals to a remote site.
 28. Themethod of claim 27, wherein the communication circuit further comprisesa telephone line communication circuit.
 29. The method of claim 21wherein the monitor includes a clock circuit and further including thestep of: (e) providing a second output signal to the patient at dailyintervals to remind the patient to grasp the momentary contactelectrodes.
 30. The method of claim 21 wherein the monitor includes atext display communicating with the atrial flutter detector circuit andfurther including the steps of: (e) providing text messages instructingthe patient in touching the first and second momentary contactelectrodes and remaining in contact with the elements prior togeneration of the output signal.
 31. The monitor of claim 21, furthercomprising: e) storing ECG data in a cascading memory having a pluralityof memory slots, f) tagging the ECG data with an age indication stamp;f) directing the stored ECG data into a memory slot currently storingECG data having an oldest age indication stamp.
 32. The method of claim21, further comprising the step of storing baseline ECG data innonvolatile memory and comparing the collected ECG signal to the storedbaseline ECG data.
 33. The method of claim 21, wherein step (d) furthercomprises providing the signals with at least one of a light, avibrating mechanism, a display, and an audible alarm.
 34. The method ofclaim 21, wherein the momentary contact electrodes are capacitivelycoupled.
 35. The method of claim 21, wherein step (c) further comprisestesting for the arrhythmia using more than one method.
 36. The method ofclaim 35, wherein step (d) further comprises providing the first signalwhen any of the methods indicate the likelihood is above a predeterminedthreshold.
 37. The method of claim 21, further comprising the step ofstoring baseline ECG data, wherein step (c) further comprises comparingthe collected data to the baseline data to determine the likelihood of aprolonged QT interval.
 38. A long-term monitor using scheduledshort-term acquisition of data from a patient for detecting anarrhythmia, the monitor comprising: (a) a first and second momentarycontact electrode for momentarily receiving ECG signals from thepatient; (b) a detector circuit communicating with the first and secondelectrodes and executing a stored program to: (i) receive the ECGsignals from the patient touching the first and second momentary contactelectrodes; (ii) detect a likelihood that the patient is experiencingthe arrhythmia; and (iii) provide a first output signal to the patientif the likelihood is above a predetermined threshold and otherwiseproviding to the patient a second output signal indicating that thelikelihood is not above the predetermined threshold; and (c) a cascadingmemory having a plurality storage locations configured to store receivedECG signals, wherein an age identifier corresponds to each received ECGsignal, and wherein newly received ECG signals are stored in the storagelocation whose data corresponds to the oldest age identifier.
 39. Themonitor of claim 38, further comprising a sensor in communication withat least one of the momentary contact electrodes and the detectorcircuit that activates the circuit only upon a determination that thepatient is touching the at least one contact electrode.
 40. The monitorof claim 39, wherein at least one of the momentary contact electrodes isconfigured to constantly contact the patient, wherein the secondmomentary contact electrode is selectively engageable by the patient,and wherein the sensor activates the detector circuit upon adetermination that the patient is touching both electrodes.
 41. Themonitor of claim 38, wherein the momentary contact electrodes areconfigured to constant contact the patient, further comprising timingcircuitry that enables the detector circuit to receive the ECG signalsfor a short period of time substantially less than a daily interval. 42.The monitor of claim 38 wherein the momentary contact electrodes arehandles graspable by the patient's right and left hands.
 43. The monitorof claim 38 wherein the momentary contract electrodes are finger padssized to contact the patient's fingers on the left and right hand. 44.The monitor of claim 38 wherein the momentary contact electrodes areoperators for switches and wherein the detector circuit communicateswith the switches to monitor ECG signals only when the switches areactivated by a pressing inward of the switch operators by contact withthe patient.
 45. The monitor of claim 38 further including anilluminating indicator and wherein the first and second outputs to thepatient are different illuminations of the indicator.
 46. The monitor ofclaim 38 further including a communication circuit and wherein thedetector circuit further (iv) communicates the ECG signals to thecommunication circuit for transmission to a remote site.
 47. The monitorof claim 46, wherein the communication circuit further comprises atelephone line communication circuit.
 48. The monitor of claim 46,wherein the communication circuit further comprises Bluetooth™.
 49. Themonitor of claim 46, wherein the communication circuit further comprisesan infrared module.
 50. The monitor of claim 38 further including analarm clock circuit providing an output signal to the patient to remindthe patient to contact the electrodes for a reading.
 51. The monitor ofclaim 38 further including a text display communicating with thedetector circuit to provide text messages instructing the patient intouching the momentary contact electrodes and remaining in contact withthe electrodes prior to generation of the output signal.
 52. The monitorof claim 38, wherein the output signals comprise at least one of alight, a vibrating mechanism, a display, and an audible alarm.
 53. Themonitor of claim 38, wherein the electrodes are capacitively coupled.54. The monitor of claim 38, wherein the memory further includes anonvolatile storage location configured to receive a historical baselineECG sample, wherein the baseline ECG sample is compared to the receivedECG sample to detect the arrhythmia.
 54. A method of long termmonitoring a patient for an arrhythmia using a monitor having a firstand second momentary contact electrode sized to contact a patient, andincorporating a detector circuit communicating with the first and secondmomentary contact electrode, the method comprising the steps of: (a)touching at least one of the momentary contact electrodes; (b) at nomore than a predetermined interval, collecting from the patient an ECGsample when the patient touches the momentary contact electrodes,wherein the data is collected for a short period of time substantiallyless than a daily interval; (c) detect by the detector circuit alikelihood that the patient is experiencing at least the arrhythmia; (d)provide a first signal to the patient when the likelihood is above apredetermined threshold and otherwise providing to the patient a secondoutput signal indicating that the likelihood is not above thepredetermined threshold; e) storing ECG data in a cascading memoryhaving a plurality of memory storage locations; f) assigning an ageindicator to each stored ECG signal; g) directing the stored ECG datainto a memory slot currently storing ECG data having an oldest ageindicator.
 55. The method of claim 54, wherein step (a) furthercomprises sensing that the patient is touching at least one of themomentary contact electrodes.
 56. The method of claim 54, wherein step(a) further comprises placing the contact electrodes in constant contactwith the patient.
 57. The method of claim 54, wherein step (a) furthercomprises placing one contact electrode in constant contact with thepatient, wherein the patient momentarily touches the other electrode,further comprising the step of sensing that the patient is touching bothcontact electrodes.
 58. The method of claim 54 wherein step (b) isconducted in the morning after the patient wakes.
 59. The method ofclaim 54 wherein the monitor includes a communication circuit andfurther including the step of: (e) communicating of the recorded ECGsignals to a remote site.
 60. The method of claim 59, wherein step (e)further comprises communicating previously stored ECG signals to theremote site.
 61. The method of claim 59, wherein the communicationcircuit further comprises a telephone line communication circuit. 62.The method of claim 54 wherein the monitor includes a clock circuit andfurther including the step of: (e) providing a second output signal tothe patient at daily intervals to remind the patient to grasp themomentary contact electrodes.
 63. The method of claim 54 wherein themonitor includes a text display communicating with the atrial flutterdetector circuit and further including the steps of: (e) providing textmessages instructing the patient in touching the first and secondmomentary contact electrodes and remaining in contact with the elementsprior to generation of the output signal.
 64. The method of claim 54,further comprising the step of storing baseline ECG data in nonvolatilememory and comparing the collected ECG signal to the stored baseline ECGdata.
 65. The method of claim 54, wherein step (d) further comprisesproviding the signals with at least one of a light, a vibratingmechanism, a display, and an audible alarm.
 66. The method of claim 54,wherein the momentary contact electrodes are capacitively coupled. 67.The method of claim 54, wherein step (c) further comprises testing forthe arrhythmia using more than one method.
 68. The method of claim 67,wherein step (d) further comprises providing the first signal when anyof the methods indicate the likelihood is above a predeterminedthreshold.
 69. The method of claim 54, further comprising the step ofstoring baseline ECG data, wherein step (c) further comprises comparingthe collected data to the baseline data to determine the likelihood of aprolonged QT interval.
 70. The method of claim 54, whererin thearrhythmia comprises at least one of atrial flutter and atrialfibrillation.
 71. A method of long term monitoring a patient for anarrhythmia using a monitor having a first and second momentary contactelectrode sized to contact a patient, and incorporating a detectorcircuit communicating with the first and second momentary contactelectrode, the method comprising the steps of: (a) touching at least oneof the momentary contact electrodes; (b) at no more than a predeterminedinterval, collecting from the patient an ECG sample when the patienttouches the momentary contact electrodes, wherein the data is collectedfor a short period of time substantially less than a daily interval; (c)determining at the detector circuit whether the patient is experiencingthe arrhythmia, including: (i) using a first detection method todetermine a first likelihood that the patient is experiencing thearrhythmia; (ii) using a second detection method to determine a secondlikelihood that the patient is experiencing the arrhythmia; and (d)provide a first output signal to the patient when at least one of thetwo likelihoods is above a predetermined threshold and otherwiseproviding to the patient a second output signal indicating that thelikelihood is not above the predetermined threshold.
 72. The method asrecited in claim 71, further comprising: e) storing ECG data in acascading memory having a plurality of memory storage locations; f)assigning an age indicator to each stored ECG signal; g) directing thestored ECG data into a memory slot currently storing ECG data having anoldest age indicator.
 73. The method of claim 71, wherein step (a)further comprises sensing that the patient is touching at least one ofthe momentary contact electrodes.
 74. The method of claim 71, whereinstep (a) further comprises placing the contact electrodes in constantcontact with the patient, wherein step (b) is performed at predeterminedintervals.
 75. The method of claim 71, wherein step (a) furthercomprises placing one contact electrode in constant contact with thepatient, wherein the patient momentarily touches the other electrode,further comprising the step of sensing that the patient is touching bothcontact electrodes.
 76. The method of claim 71 wherein step (b) isconducted in the morning after the patient wakes.
 77. The method ofclaim 71 wherein the monitor includes a communication circuit andfurther including the step of: (e) communicating of the recorded ECGsignals to a remote site.
 78. The method of claim 77, wherein step (e)further comprises communicating previously stored ECG signals to theremote site.
 79. The method of claim 78, wherein the communicationcircuit further comprises a telephone line communication circuit. 80.The method of claim 71 wherein the monitor includes a clock circuit andfurther including the step of: (e) providing a second output signal tothe patient at daily intervals to remind the patient to grasp themomentary contact electrodes.
 81. The method of claim 71 wherein themonitor includes a text display communicating with the detector circuitand further including the steps of: (e) providing text messagesinstructing the patient in touching the first and second momentarycontact electrodes and remaining in contact with the elements prior togeneration of the output signal.
 82. The method of claim 71, furthercomprising the step of storing baseline ECG data in nonvolatile memoryand comparing the collected ECG signal to the stored baseline ECG data.83. The method of claim 71, wherein step (d) further comprises providingthe signals with at least one of a light, a vibrating mechanism, adisplay, and an audible alarm.
 84. The method of claim 71, wherein themomentary contact electrodes are capacitively coupled.
 85. The method ofclaim 71, further comprising the step of storing baseline ECG data,wherein step (c) further comprises comparing the collected data to thebaseline data to determine the likelihood of a prolonged QT interval.86. A method of long term monitoring a patient for an arrhythmia using amonitor having a plurality of contact electrode sized to contact apatient, and incorporating a detector circuit communicating with theelectrodes, the method comprising the steps of: (a) placing the contactelectrodes in contact with the patient; (b) collecting from the patientat least two channels of ECG data on a continuous basis; (c) determiningat the detector circuit whether the patient is experiencing thearrhythmia, including: (i) using a first detection method on a firstchannel of data to determine a first likelihood that the patient isexperiencing the arrhythmia; (ii) using a second detection method on asecond channel of data to determine a second likelihood that the patientis experiencing the arrhythmia; and (d) provide a first output signal tothe patient when at least one of the two likelihoods is above apredetermined threshold and otherwise providing to the patient a secondoutput signal indicating that the likelihood is not above thepredetermined threshold.
 87. The method as recited in claim 86, furthercomprising selecting a channel exhibiting a greatest R-R intervalcompared to the other channel.
 88. The method as recited in claim 87,wherein the first detection method further comprises analyzing the R-Rinterval from the selected channel.
 89. The method as recited in claim88, wherein the second detection method is applied to the non-selectedchannel.
 90. The method as recited in claim 86, further comprisingstoring recent ECG data in nonvolatile memory when at least one of thetwo likelihoods is above the predetermined threshold.
 91. The method asrecited in claim 86, further comprising storing recent data in volatilememory upon an arrhythmatic patient symptom.